Simplify the following expression: $k = \dfrac{10r - 30q}{20q + 5} - \dfrac{5r}{20q + 5}$ You can assume $p,q,r \neq 0$.
Explanation: Since the expressions have the same denominator we simply combine the numerators: $k = \dfrac{10r - 30q - (5r)}{20q + 5}$ $k = \dfrac{5r - 30q}{20q + 5}$ The numerator and denominator have a common factor of $5$, so we can simplify $k = \dfrac{r - 6q}{4q + 1}$